Rotary fan or pump.



No. 69|,609. v Patented Ian. 2|, I902. s. c. DAV|DSON. RUTABY FAN 0R PUMP.

(Application filed Mar. 21, 1899.) (No Model.) 2 Sheets-Sheet I.

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'No. 69|,609.' Patented Jan. 2|, I902.

S. C. DAVIDSON.

ROTARY FAN ORPUMP.

(Application filed m. 21, 1899.)

(No Model.)

2 Sheets$heet 2.

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UNITED STATES PATENT OFFICE.

SAMUEL OLELAND' DAVIDSON, OF BELFAST, IRELAND.

ROTARY FAN OR PUMP.

SPECIFICATION forming part of Letters Patent No. 691,609, dated January 21, 1902. Application filed March 21.1899. Serial No. 709,919. on model.)

To ctZZ whom it may concern:

Be it known that I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works,

Belfast, Ireland, have invented certain new and useful Improvements in Rotary Fans or Pumps, of which the following is a specification. w

This invention relates to centrifugal fans or pumps, and constitutes a specific improvement in mode of construction over the generic inventionset forth in my application, Serial No. 691,495, filed September 21, 1898. The invention set forth in that application provides a centrifugal fan or pump the rotary member of which comprises numerous thin elongated blades arranged lengthwise in approximately axial direction and in substantially drum form, so as to inclose within them a relatively large and practically unobstructed intake-chamber, the blades being in transverse section arranged relatively to the axis 1 and direction of rotation to carry the fluid with them rotatively and discharge it tangentially and the stationary member of which is so constructed as to permit tangential escape of the fluid discharged from the blades. Such stationary member may comprise the ordinary helicoidal casing or the rotary member may be rotated without any casing, the stationary member in this, case consisting merely of asuitable bearing for the operating-shaft of the rotary member. In such fans the blades are most conveniently supported at one end. by being fastened to a disk (or a series of arms) which is mounted on the axial shaft, and the opposite end is annularly supported in some suitable manner. In my said I application I have illustrated different modes of connecting the overhanging or annularlysupported ends of the blades, one method being by forming these blades at that end with laterally-projectingears or flanges, the ear of each blade overlapping the next and being riveted thereto, so that the entire series ofblades are annularly joined together at the overhanging ends, and another method being by riveting the overhanging ends of the blades to an encircling ring or annulus. It is found in practice that the riveting of the blades to each other or to such ring inevitably involvessome distortion of the barrel-like structure formed by the assembled blades out of a true concentric circle at their overhanging ends. It is also found, especiallyin a fan with relatively long blades, that the driving strain when applied only at the end of the fan at which the blades are supported on the disk or its equivalent results in some distortion or straining of the fan by the transmission of the propulsive thrust from the one end of the blades to the opposite or overhangingend thereof through the blades themselves alone,whereby the overhanging or aunularlysupported end ofthe series of blades lags behind, so as to tend to twist or bend the blades.

One object of my present invention hence is to provide such a fan in which the overhanging or annularly-supported ends of the, blades may be rigidly supported or trussed and by which, if need be, they may be adjusted so'that the distortion of the overhanging ends of the blades out of a true circle is readily corrected, so that when the fan is in motion they shall revolve in a true circle.

A further object-is to communicate the propulsive thrust or stress directly from the 0perating-shaft to the overhanging ends of the series of blades, so that they shall be capable of withstanding the powerful strain's developed by centrifugal force when the fan is revolving at high speed.

It is important that these objects should be accomplished with the minimum of obstruction to the flow of the fluid.

In carrying my invention intotefiect the overhanging ends of the blades are connected together, preferably by being riveted either to each other or to a separate ring or band, and the blades thus annularly supported are preferably provided with attachments at suitable intervals for wire or other stays, hereinafter called the stays, which extend to overhanging end of the series of blades. The

inner ends of the stays are preferably attached to the boss by screws or the like, and their outer ends are preferably passed through holes in the attachments on the overhanging end of the fan and are screw-threaded to receive nuts, so that by tightening up the latter the stays are put into more or less tensile strain, as may be necessary to draw the overhanging end of the fan into accurate adjust-ment.

In the accompanying drawings, Figure 1 is a sectional elevation, on the line A B of Fig. 2, of a rotary fan or pump constructed in accordance with my invention. Fig. is an end elevation of the fan or pump as seen from the left hand of Fig. 1.

In the drawings, a C6 are the blades, and b is a disk to which they are shown as fixed at one end. The disk b is carried by a boss or center piece 0, keyed on the shaft d. As the blades a a are of considerable axial length, they therefore overhang the supporting-disk b to an equivalent extent. For the purpose of imparting the requisite strength and rigidity to said blades and to best resist the centrifugal force to which they are subjected when revolving at high speeds the overhanging ends are preferably connected together by an encircling ring or band (2, and upon this ring are mounted bracket attachments fat suitable intervals for the attachment of wire or other stays g, leading therefrom to correspondingly-located attachments h around the projecting end or apex of the boss 0, as shown. The outer ends of the stays g are preferably passed through holes in the bracket attachmentsf on the ring 6 and are screwed at the ends for nuts 5 to be mounted thereon. inner ends of the stays g are attached as tangents to and around the end of the boss 0, preferably by screws it, through eyeholes formed in the ends of the stays g and which are attached to the side of the boss 0. In case the ring 6 is omitted the outer ends of the stays may be connected directly to the blades, which in this case may be connected together in any suitable manner, as by riveting, as before described. The tightening of the nuts 6 on the outer ends of the stays g puts said stays into more or less tension, as required, to draw the overhanging end of the fan into true central adjustment relatively to the axis of the fan, and when the fan is driven at high velocities the effect of the centrifugal force developed thereby upon said blades is counteracted by the tensile strain of the stays The g, acting on the annularlysupported end of the fan.

I claim as my invention the following-defined novel features, substantially as hereinbcfore set forth, namely:

1. A centrifugal fan or pump the rotary member of which comprises essentially numerous thin blades arranged in drum form, so as to inclose within them an intake-chamber into which the fluid operated on is taken axially, and from which it is discharged circumferentially, a shaft, and a series of stays connected from said shaft to said series of blades, said stays being arranged tangentially to said shaft, with their inner ends in advance of their outer ends, whereby they serve to communicate the propulsive stress directly from the shaft to the series of blades.

2. A centrifugal fan or pump the rotary member of which comprises essentially numerous thin blades arranged in drum form, so as to inclose within them an intake-chamber into which the fluid operated on is taken axially, and from which it is discharged circumferentially, a central hub or boss by which the rotary member is mounted on its axial shaft, having a connection with one end of the series of blades, and a series of stays connected from said boss to said annular support, said stays being arranged tangentially to said boss with their inner ends in advance of their outer ends, whereby they serve to communicate the propulsive stress directly from the boss to the annular support.

3. A centrifugal fan or pump comprising numerous thin blades arranged in drum form,

with a central hub or boss connected to oneend of the series of blades fol-supporting them upon a shaft, and an annular support for the opposite end of said series of blades, attaching-studs on said boss, and a series of tangential stays connected from said attaching-studs on said boss to said annularsupport, and nuts for adjusting the strain on said stays.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

SAMUEL CLELAM) DAVIDSON.

Witnesses GEORGE GooLD WARD, HUGH TAYLOR COULTER. 

